Mechanical, electronic, and thermodynamic properties of zirconium carbide from first-principles calculations

Abstract

Mechanical, electronic, and thermodynamic properties of zirconium carbide have been systematically studied using the ab initio calculations. The calculated equilibrium lattice parameter, bulk modulus, and elastic constants are all well consistent with the experimental data. The electronic band structure indicates that the mixture of C 2p and Zr 4d and 4p orbitals around the Fermi level makes a large covalent contribution to the chemical bonds between the C and Zr atoms. The Bader charge analysis suggests that there are about 1.71 electrons transferred from each Zr atom to its nearest C atom. Therefore, the Zr–C bond displays a mixed ionic/covalent character. The calculated phonon dispersions of ZrC are stable, coinciding with the experimental measurement. A drastic expansion in the volume of ZrC is seen with increasing temperature, while the bulk modulus decreases linearly. Based on the calculated phonon dispersion curves and within the quasi-harmonic approximation, the temperature dependence of the heat capacities is obtained, which gives a good description compared with the available experimental data.

Pressure‐induced enhancement of mechanical performance in ZrC system

“…In Table 3, we also compared our calculation with other experimental and theoretical results. As shown in Table 3, our theoretical elastic constants are consistent with the experimental values [45,46] and other theoretical results [34,35,47]. By comparing the three elastic constants, we find that C In order to investigate the mechanical parameters of Zr 4 C 4 , bulk modulus B (Pa), shear modulus G (Pa), Young's modulus E (Pa), Poisson's ratio ν, G/B ratio, Cauchy pressure C 0 (Pa), universal anisotropy index A u , hardness H (Pa), and machinability index μ M for a polycrystalline material with cubic crystal system can be calculated from by using Voigt-Reuss-Hill approximations [48][49][50][51][52][53][54][55], as follows:…”

“…Our theoretical lattice parameter of 4.698 Å agrees well with the experimental value of 4.698 Å [33]. It is to be noted that other theoretical calculations displayed results in the range of 4.68-4.72 Å [34,35]. The unit-cell volume of Zr 4 C 4 decreased at a rate from 4% to 2% in every increment of 10 GPa.…”

Temperature‐dependent elastic and thermodynamic properties of ZrC, HfC, and their solid solutions (Zr0.5Hf0.5)C

“…6,7 Although some research has discussed about the elastic and thermodynamic properties of ZrC and HfC using first-principles calculations, few studies have investigated their combination in solid solutions, much less on their temperature-dependent properties. [8][9][10][11] For example, Guo et al 12 calculated the electronic properties, dynamic stabilities, and mechanical properties of ZrC, HfC, and their solid solutions. The solid solutions of ZrC and HfC are in principle retaining its pristine metals, and their mechanical properties are comparable to those of ZrC and HfC.…”

“…Although some research has discussed about the elastic and thermodynamic properties of ZrC and HfC using first‐principles calculations, few studies have investigated their combination in solid solutions, much less on their temperature‐dependent properties 8–11 . For example, Guo et al 12 .…”

Mechanical, structural, and thermodynamic properties of TaC-ZrC ultra-high temperature ceramics using first principle methods

“…More recently, the stability of ZrC under high pressure (up to 150 GPa) and high temperature (up to 2000 K) was studied by Lijie Tan et al [12]. The theoretical approach into the properties of ZrC and ZrCN was also carried out using Density Functional Theory (DFT), indicating DFT is such a powerful method to predict the properties of conventional compounds and new designed materials [13][14][15].…”